The family of a 14-year-old Brooklyn girl whose body was dumped and burned on a beach after she was killed called the suspect a coward for allegedly suffocating her because he thought she was pregnant.

Prosecutors at Christian Ferdinand’s arraignment yesterday said the 20-year-old suspect on Jan. 4 pressed a pillow against Shaniesha Forbes’ face until she stopped breathing.

Two days later, the missing girl’s burned body was found at Gerritsen Beach.

But her family said the girl hadn’t been pregnant.

“You had the courage and the balls to kill her . . . and lay her on the beach,” said her cousin Kerry-Anne Thomas to the suspect. “But you couldn’t go to the pharmacy to buy a pregnancy test to find out if it was true.”

Sources said the two had met via Facebook.

“Honestly, there shouldn’t have been a relationship,” Thomas said. “He was a 20-year-old man and she was a 14-year-old child.”

NYPD Commissioner Ray Kelly said the suspect hid Shaniesha’s body in a suitcase on a roof for two days before carrying the corpse to the beach and burning it.

“He believed that the victim was pregnant and that she wouldn’t get an abortion,” said Police Commissioner Ray Kelly. “And she was murdered as a result.”

Ferdinand was not required to make a plea. He was arrested Tuesday in Maine after the medical examiner determined how the girl had died. Detectives said Ferdinand confessed.